As Oscar Cardozo began his run-up for what turned out to be Paraguay's winning penalty, Japan's players knelt together on the halfway line, hardly daring to look. And as the ball rolled into the left-hand corner of the net, some heads dropped to the floor, their World Cup hopes decapitated.

Meanwhile 20 yards away, those in red and white began a long and tearful victory charge towards Cardozo, whose nerveless penalty settled a highly nervy encounter. Paraguay scored all five of their spot-kicks, while only Yuichi Komano, who smashed his shot against the bar, missed for Japan. By such margins are games decided.

"There was fear and tension," the Paraguay coach, Gerardo Martino, said. "Everyone knows it is unfair to settle a game like this. But when you win the tension is released and so many things go through your mind. That was the reason for the tears."

"This is our best success," he added. "We are having a party. We celebrate with the rest of Paraguay. Let them enjoy it. The players made a huge effort. This is a success. We have made it to the quarter-finals. We know we are in the best eight in the world."

It was perhaps inevitable that the knockout stages of this World Cup would produce a stinker at some point, after 21 goals in the opening six second-round matches, and it duly arrived in Pretoria today. Tension gripped the game, with Paraguay playing tidy but unthreatening football and Japan content to counter, and never let go.

Bursts of sustained excitement were rare, although there were chances early on. After 20 minutes, Lucas Barrios spun around Yuichi Komano before side-footing weakly at Eiji Kawashima and could only watch as Japan zipped up the pitch before Daisuke Matsui smashed a whirling shot over the scrambling Justo Villar and against the bar.

Just before the half-hour, Roque Santa Cruz missed perhaps the best chance of the match, pulling his shot from a corner wide from eight yards. A goal would have spared us what followed.

Paraguay had the better of the second half but long before the end both teams seemed content to drift into the choppier waters of extra-time and penalties. Nelson Valdez did prompt a few gasps when he took Claudio Morel's pass on the spin only for Kawashima to dash out to smother, and he also came close when flicking over the bar after a scramble just outside the six-yard box. Japan's best response came from a 25-yard free-kick from Keisuke Honda, whose toe-poke was going wide when Justo Villar pushed it round the post.

But these moments offered rare respite from the general turgidity. "It was perhaps not what people wanted to watch but no team has anything to reproach themselves about," Martino said. "Japan played as they usually do. The go back, wait, counter. They were difficult."

That was true enough, but Paraguay lacked the confidence – and probably the desire – to risk more in trying to break them down.

Still, Japan have contributed much to this World Cup, and their manager, Takeshi Okada, said he was proud of his players' performances. "I have no regrets," he said. "The players were wonderful. The represented Japan and Asia as a whole. It is very difficult to say for one single reason why we couldn't score. We are not a team who can score numerous goals."

"It is my responsibility because as the head coach I should have been more insistent on winning," he added. "But even with extra time and penalties, our objective was to score and win. What we have done is not sufficient."

When Okada was asked if he would carry on he was frank. "I don't think I will continue for four more years," he said. "Probably I won't."

Paraguay certainly do continue and will face Spain in the quarter-finals on Saturday night. Remarkably, of the five South American teams in this World Cup, four are still standing. "South America is peaking," said Martino. "We have so many in the last eight." They could even have four teams in the semi-finals, given the draw, but on this evidence you imagine Paraguay's next opponents Spain would not be too worried about what lies in wait.

This is not a news report and may contain views expressed by the author which are not supported by GNM.